Abstract: In order to optimize their Al₂O₃-SiO₂ raw materials,anorthite based insulation refractories were prepared by the in-situ sintering process combined with the foaming method after sintering at 1 350 ℃ for 3 h,using green and pollution-free kaolin,kyanite,andalusite and sillimanite as Al₂O₃-SiO₂ raw materials,and industrial CaCO₃ as the CaO source.Effects of Al₂O₃-SiO₂ raw material types on the physical properties,phase composition and microstructure were investigated.The results are as follows.All samples prepared by different Al₂O₃-SiO₂ raw materials have hexagonal flake anorthite and a small amount of mullite and corundum.Their bulk density decreases in the order of using kaolin,andalusite,kyanite and sillimanite as the Al₂O₃-SiO₂ raw material,but their apparent porosity increases and their thermal conductivity decreases in this order.Moreover,in the sample with kaolin,the bonding between anorthite crystals on the pore walls is closer than that of the other samples,which is conducive to increasing the compressive strength.The bonding between anorthite crystals on pore walls gradually decreases in the order of using kyanite,andalusite and sillimanite as the Al₂O₃-SiO₂ raw material,thus their compressive strength decreases accordingly.In comprehensive consideration,the properties of the sample from kyanite are the optimal.Its apparent porosity,thermal conductivity and cold compressive strength are 84.6%,0.141 W·m^-1·K^-1 and 1.89 MPa,respectively.

Key words: anorthite based insulation refractories, Al₂O₃-SiO₂ raw materials, compressive strength, thermal conductivity, microstructure

摘要： 为优化制备钙长石质隔热耐火材料用铝硅系原料,以绿色无污染的高岭土、蓝晶石、红柱石和硅线石为铝硅系原料,工业CaCO₃为CaO源,采用发泡法结合原位反应烧成工艺,经1 350 ℃保温3 h后获得了钙长石质隔热耐火材料。研究了铝硅系原料种类对合成材料物理性能、物相组成和显微结构的影响。结果表明:不同铝硅系原料所制试样均生成了六边形片状钙长石,并存在少量莫来石和刚玉。试样的体积密度按使用高岭土、红柱石、蓝晶石、硅线石为铝硅系原料的次序依次降低,显气孔率依次升高,热导率依次降低;以高岭土为铝硅系原料所制试样的孔壁中钙长石晶体结合紧密,赋予其较佳的耐压强度,以蓝晶石、红柱石及硅线石为铝硅系原料时,试样的耐压强度依次减小,因为孔壁上钙长石晶体间结合程度逐渐减弱。综合考虑,以蓝晶石为铝硅系原料所制试样的综合性能最佳,其显气孔率、热导率和常温耐压强度分别为84.6%、0.141 W·m^-1·K^-1和1.89 MPa。

关键词: 钙长石质隔热耐火材料, 铝硅系原料, 耐压强度, 热导率, 显微结构